MEDIA_IOC_DEVICE_INFO — Query device information
int ioctl( | int fd, |
| int request, | |
struct media_device_info *argp); |
All media devices must support the MEDIA_IOC_DEVICE_INFO
ioctl. To query device information, applications call the ioctl with a
pointer to a struct media_device_info. The driver fills the structure and returns
the information to the application.
The ioctl never fails.
Table L.1. struct media_device_info
| char | driver[16] | Name of the driver implementing the media API as a
NUL-terminated ASCII string. The driver version is stored in the
Driver specific applications can use this information to verify the driver identity. It is also useful to work around known bugs, or to identify drivers in error reports. |
| char | model[32] | Device model name as a NUL-terminated UTF-8 string. The
device version is stored in the device_version
field and is not be appended to the model name. |
| char | serial[40] | Serial number as a NUL-terminated ASCII string. |
| char | bus_info[32] | Location of the device in the system as a NUL-terminated ASCII string. This includes the bus type name (PCI, USB, ...) and a bus-specific identifier. |
| __u32 | media_version | Media API version, formatted with the
KERNEL_VERSION() macro. |
| __u32 | hw_revision | Hardware device revision in a driver-specific format. |
| __u32 | driver_version | Media device driver version, formatted with the
KERNEL_VERSION() macro. Together with the
driver field this identifies a particular
driver. |
| __u32 | reserved[31] | Reserved for future extensions. Drivers and applications must set this array to zero. |
The serial and bus_info
fields can be used to distinguish between multiple instances of otherwise
identical hardware. The serial number takes precedence when provided and can
be assumed to be unique. If the serial number is an empty string, the
bus_info field can be used instead. The
bus_info field is guaranteed to be unique, but
can vary across reboots or device unplug/replug.
On success 0 is returned, on error -1 and the errno variable is set appropriately. The generic error codes are described at the Generic Error Codes chapter.